basic equations

solve for x,y, and z
31x+12y-24z=105
18x+24y+z=77
12x+6y+4z=5
ive tried doing this several ways, but i get different answers every time. all i am able to really do is get rid of y by multiplying the 3rd equation by 4. after that im just kind of stuck.

solve for x,y, and z
31x+12y-24z=105
18x+24y+z=77
12x+6y+4z=5
ive tried doing this several ways, but i get different answers every time. all i am able to really do is get rid of y by multiplying the 3rd equation by 4. after that im just kind of stuck.

You should be able to continue from here, but check my calculations though.